(1) Technical Field
This invention pertains to safety valves useful to control flow in a well conduit. The invention particularly pertains to safety valves actuated to close by flow and having a retrievable weight assembly on which weight may be varied to change the closing flow rate of the safety valve.
(2) Background Information
Patents have been obtained for a member of safety valve structures actuated to close by flow. Examples are U.S. Pat. Nos. 3,070,119 and 3,603,394 to Raulins, 3,126,908 to Dickens, and 3,189,044 to Sizer. Each of these patented structures must be retrieved from the well or a well conduit to change the flow rate at which they are actuated to close.